Heretofore, known methods for treating gastroesophageal reflux disease, which is a benign disorder caused by degradation of the function of the cardiac sphincter at the entrance of the stomach, include oral administration of a proton pump inhibitor (PPI) that decreases the amount of gastric acid, the Nissen fundoplication technique (fundoplication technique) that involves wrapping a part of the stomach around the esophagus, the LINX technique that involves squeezing the esophagus with a magnet band or rubber band, the transoral incisionless fundoplication (TIF) technique that involves pulling the cardiac part under peroral endoscopy and stapling the cardiac part in the pulled state to form a valve, etc.
In addition, the methods described in, for example, PTL 1 and PTL 2 are known as other methods for treating gastroesophageal reflux disease. The method described in PTL 1 involves removing tissue from the surface of a gastrointestinal tract, such as the esophagus, the stomach, or the like, and re-constructing the body passageway by utilizing the healing reaction. In PTL 2 , the gastrointestinal tract is constricted by deliberately causing scars to form by incising at least one of the mucosal layer and the submucosal layer in the gastroesophageal junction or the stomach.